Maurice hutin and maurice leblanc



(No Models) I l M. HUTIN & M. LEBLANC,

TELEPHONY AND TELEGRAPHY. I No: 596,017. .Patqnted D90 .21,1891;

INVENTOBS Y mm:

ATTORNEY.

TNE uomus FEYERS c0, PHOTO-Limo, whsumamm D. c

UNITED STATES PATENT EETCE.

MAURICE HUTIN AND MAURICE LEBLANO, OF PARIS, FRANCE, ASSIGNORS TO THE SOOIETE ANONYME POUR LA TRANSMISSION DE LA FORGE PAR LELEGTRIOITE, OF sAME PLACE.

TELEPHONY AND TELEG RAPHY.

SPECIFICATION forming part of Letters Patent No. 596,017, dated December 2 897- Application filed January 31, 1893. $eria1ll'o. 460,318. (No model) Patented in France sa a b 3, 1891, No. 215,901, and in England December 27, 1891, No. 23,892.

To all whom it may concern.-

Be it known that we, MAURICE HUTIN and MAURICE LEBLANC, citizens of the Republic of France, and residents of the city of Paris, in

the Department of the Seine, in the Republic of France, have invented certain new and. useful Improvements in Telephony and Telegraphy, (for which we have obtained Letters Patent in France, No.-215,901, dated September 3, 1891, and in Great Britain, No. 23,892, dated December 27, 1891,) of which the following is a specification.

Our invention has reference to improvements in telephony and telegraphy; and it comprises a new method of and apparatus for transmitting telephonic or telegraphic messages.

A characteristic feature of our method of operation is that the source or sources of electrical energy may be located at any single point on the line, and is preferably located at a point removed from the transmitting or receiving station-that is to say, at a central station-so that in telephonic systems no batteries are required at the subscribers stations and in telegraphic systems those in charge of way-stations are relieved of the care for the maintenance of batteries.

In the accompanying drawings,which form a part of this specification, we have shown, in Figure 1, a diagram illustrating our invention for transmission and reception of telephonic messages. Fig. 2 is a cross-section of a telephone-receiver adapted to our system; Fig. 3, a vertical section of a microphonetransmitter particularly constructed for use in connection with our method of operation. Fig. 4 is a top view of the same with the diaphragm removed.

Like numerals of reference indicate like parts.

Prior to our invention telephony was practiced either by throwing upon the line a unidirectional substantially constant current 45 and varying the strength of the current by and in accordance with sound-waves or by having the line normally uncharged and producing upon the same alternating currents by and in accordance with sound-waves.

Our new system differs from both of the old systems in this, that we produce and normally maintain upon the line substantially uniform alternating currents, and these currents are then varied by and in accordance with sound-waves in a manner that will be explained farther on. The alternating current employed should be such that its own alternations are not felt in the telephone-receiver-that is to say, the normal line-currents should produce no sound, or at least no obtrusive sound, in the receivers.

Referring now particularly to Fig. 1, there is shown upon a line 1, which here is represented'as grounded at both ends, a-transmitting-station 2, a receiving-station 3, and a generating-station 4. At the generatingstation there are generated and transmitted over the line alternating currents of suitable tension and of such high frequency that the vibrations resulting therefrom in a telephonereceiver are barely, if at all, audible. We have found by experiment that alternating currents of the frequency ten thousand fulfil this condition. For the purposes of our invention it is of no consequence by what means the line is charged with these highfrequency currents; but we have shown a means suitable for this purpose,without, however, being confined to the same.

As the ultimate source of current we have shown an electric battery 5, which may be a storage battery, one pole of which is connected with a brush 6, bearing upon the metallic hub 7 of a metal disk 8, the periphery of which is divided into a great number of conducting and non-conducting segments. Upon the rim of this disk or wheel bears a brush 9, which is connected with the other pole of the battery, as shown. This disk or wheel 8 thus constitutes a circuit-breaker, 0 and if it is rotated at highspeed it is practicable to produce a very great number of interruptions in the circuit. In a shunt between the two brushes is placed a condenser 10 for suppressing sparks at the brush 9, and 5 in the circuit 11 thus formed is included the primary coil 12 of an inductional transformer, the secondary coil 13 of which is in the line trodes 22.

1. I11 this manner we obtain the desired frequency of alternating currents on the line, and a telephone-receiver included at any point in the line will be affected by these alternating currents, but the vibrations of its diaphragm will be barely audible, if audible at all. The receiver which is particularly adapted to our system is one in which there is neither a magnetic core nor a magnetic diaphragm, and is constructed, as best shown in Fig. 2, of a fixed hollow coil 14: in the line circuit and a similar coil 15 which is in series therewith and is secured to the under side of a non-magnetic and preferably non-conducting diaphragm 16. A receiver of this kind will respond more readily to alternating currents of different frequencies, since there is no hysteresis of the iron to be overcome and there is very little self-induction in such instrument. It involves the principle of the clectrodynamometer, and we therefore call such receiver an electrodynamometer-receiver. At the transmitting-station 2 there is in the line-circuit a coil 17, and in a local circuit 18 there is another coil 19 in inductive relation to the coil 17, so that the two together constitute in effect an inductorium or transformer. In this local circuit 18 is included a microphone 20, of any suitable form, and which is therefore indicated in Fig. 1 in a conventional manner only-namely, as composed of a diaphragm 21 and two carbon elec- NVe shall hereinafter describe a special construction of microphone particularly adapted to our system.

The operation of the system so far described is as follows: The alternating currents of high frequency on the line, passing through the receiver-coils, will produce vibrations of the diaphragm. Owing to the high frequency of the currents the diaphragm, which is attracted when the alternating currents are increasing, cannot at the same rate complete its return movement, owing to its inertia, which is a characteristic of all bodies. Diaphragms, although responding with tolerable ease to vibrations of numerous different frequencies, have still a fundamental note which is far below ten thousand vibrations per second. If, however, it should be found that the diaphragm responds more than it should to currents of the frequency ten thousand, then currents of a higher frequency will be used. The receiver will therefore be practieally silent. If now sounds are uttered against the transmitter-diaphragm, the local circuit 18 will have its resistance varied at the rate of and in a manner proportionate to the amplitudes of the vibrations of the diaphragm. The consequence of this is that the coil 19 reacts upon the coil 17 to increase and diminish the currents on the line at the rate of and in accordance with the amplitudes of the diaphragm. Now the vibrations of the diaphragm 21 under the influence of speech or other sounds uttered against the same have a far less frequency than the alternating currents upon the line, so that the diaphragm of the receiver will now be acted upon at these reduced frequencies-that is to say, the receiver-diaphragm, while still receiving impulses at the rate of the line-currents, now receives these impulses at one time with increasing force and at another time with decreasing force, the times and amplitudes of increase and decrease being controlled by the vibrations of the transmitter diaphragm. \Vhile the receiver diaphragm can never complete its vibrations, especially its return movements, at the rate of; the line-currents, it can and does complete vibrations at the rate at which the successive currents are increased and diminished by the action of the transmitter-diaphragm. The vibrations of the receiver-diapln'agm will therefore generally be represented by a curve similar to that which represents the sound-waves uttered against the transmitter, but will be slightly modified by superimposed sinusoidal waves. This does not prevent the recognition of the original sounds.

In this system the trouble heretofore experienced in maintaining a battery or other source of current at each transmitting-station is entirely avoided.

Instead of using an independent transformer for each transmitter we preferably use a transmitter wherein the microphonic elements themselves constitute one of the circuits of the transformer, and such transmitter we have illustrated in Figs. 3 and 4.

In a box 23 of suitable shape is located the coil 17, which is included in the line-circuit by the binding-posts 24 24. Within this coil and secured in any suitable manner to the inner walls of the same are a number of se mental pieces 22 of carbon, separated from each other by air-spaces, but all in one plane, so as to form an annulus, as it were, from which small segmental strips have been removed. On the under side of the diaphragm 21 are secured similar carbon segments 22", which when the diaphragmis in place lightly press upon the segments 22; but they are shifted with relation to the latter so as to bridge the air-spaces between them, whereby these two sets of carbon segments form a complete circuit in inductive relation to the coil 17, and thus constitute with the same a transformer in which the carbon annulus takes the place of the coil 10, (shown in Fig. 1,) and at the same time constitute an effective microphone of low resistance. It will now be seen that the line-currents of higher tension passing through the coil 17 will induce currents of like frequency but of lower tension and of great volume in the microphone-ring. The resistance of this microphone being varied bysounds uttered againstthe diaphragm, the currents in the same will be varied and will react upon the line-coil 17, all as hereinbefore described.

All that has been said about telephony applies with equal force to telegraphy, except IIO ' smaller and that in place of telephonic transmitters and receivers suitable telegraphic instruments will be used. It is then only necessary, wherever there are pieces of iron subject to magnetic action, to substitute for solid cores, cores made of iron wires or of strips insulated from each other, so as to avoid the effects of Foucault currents.

Having now fully described our invention, we claim and desire to secure by Letters Patent 1. The method of transmitting messages, consisting in passing over a line waves of alternating or varying current of such high frequency as only slightly affect the receivers and modifying the amplitudes of these waves in accordance with the desired message, substantially as described.

2. The method of transmitting speech or other sounds, consisting in passing over a line waves of alternating or varying current of such high frequency as will be barely audible in the receivers and varying the amplitudes of these waves by and in accordance with speech or other sounds, substantially as described.

3. The method of transmitting speech, consisting in passing over the line waves of alternating or varying current of slight audibility in the receivers and superposing thereon Waves of current corresponding to vocal waves, substantially as described.

4. The method of transmitting speech, con; sisting in putting upon the line alternating or varying waves of current inaudible, or nearly so, in receivers and inductively superposing Waves of current corresponding to the vocal waves received by a transmitter.

5. The method of transmitting speech,-consisting in passing over a line or circuit, including the receivers and transmitting devices, waves of electric current incapable or nearly incapable of producing audible tones in the receivers, and modifying the induction between the line-transmitter coil and a local coil in inductive relation thereto through the agency of voice-Waves.

6. The method of transmitting speech along a line having receivers and transmitters, consisting in producing induction between a varying or alternating current in the line of such rate as not to produce strongly-audible tones or sounds in the receiver and a local circuit in inductive relation. to a coil in the line and modifying the resistance of such 10- cal circuit by the vocal waves received by the transmitter.

7. In combination with a telephone-line having receivers thereon of means for producing in said line varying or alternating current impulses of such period as not to produce strongly-audible tones or sounds in receivers, and means such as alocal coil in inductive relation to a coil in the line, for superimposing undulations inductively transferred from the local coil to the line-coil, the 10- cal coil being provided with a telephone-transmitter in its circuit, whereby the resistance of its circuit may be varied by the waves of the voice communicated to said transmitter.

8. A system of electric transmission of messages, comprising a line, and receiving instruments means for charging the line with alternating currents of such high frequency as will barely actuate the receivers, and a transmitter operating to vary the amplitudes of the alternating currents in accordance with the desired message, substantially as de' scribed.

9. In a telephone system in which substantially uniform alternating or varying impulses are passed over the line, an inductioncoil the primary of which, is in the line and the secondary of which is local to the transmitter and connected to the said transmitter, whereby the variations of resistance set up in the transmitter by sound-waves acting thereon operate inductively upon the primary coil in the line to vary its normal current in accordance with the said sound-waves.

10. The combination, in a telephone system, of an inductorium provided with a primary coil of many turns normally traversed by substantially uniform alternating or varying currents, and also provided with a secondary coil of few turns locally connected through a transmitter for varying the resistance of said local-coil circuit as described, and for the purpose specified.

11. The method of telephoning, consisting in passing over acircuit a substantially uniform alternating or varying current, and inductively modifying said current in correspondence with sound-vibrations.

12. The method of transmitting messages I electrically, consisting in passing over a circuit a substantially uniform alternating or varying current, passing said current through a coil of an inductorium, and varying the counter-induction of said inductorium in accordance with the desired message.

13. The method of telephoning, consisting in feeding the line with a substantially uniform electric current of periodically rising and falling potential, passing said current through a counter-inductive device included' in the line-circuit, and varying the counterinduction of said device by the agency of sound-vibrations, whereby the said current is made to flow over said line in impulses or waves corresponding to the sound-vibrations.

14:. A telephonic transmitter consisting of an inductorium, one circuit of which constitutes a microphone and the other circuit of which is a coil of insulated Wire in inductive relation to the first and adapted for insertion in a line, substantially as described.

15. A telephonic transmitter consisting of an inductorium having a circuit of low resistance constituting a microphone and a circuit inductive relation to the circular microphone and adapted to be insertedin a line, and a diaphragm acting upon the microphone, substantially as described.

18. The improvement in the art of telephony I which consists in charging a line with substantially uniform alternating currents and varying these currents by and in accordance with sound-waves.

19. The improvement in the art of telephony which consists in charging a line with alternating currents the effects of which are not obtrusively perceptible in the receiver, and varying these currents by and in accordance with sound-waves.

In witness whereof we have hereunto signed our names in the presence of two subscribing witnesses.

MAURICE HUTIN. MAURICE LEBLANC. W'itnesses:

J ULES ARMENGAUD, Jeune, RoBr. M. HOOPER. 

